Lifting jack



Sept. 15, 1931., Y"

A. l.. JOHNSON y LIFTING JACK Filed Nov. 25, 192'? 2 Sheets-Sheet l Ill] m A. L. JOHNSQN LIFTING JACK Sept. 15, 1931.

2 Sheets-Sheer- 2 Filed Nov. 25, 1927 il; or casing Patented Sept. 15, 1931 UNITED STATES PATENT OFFICE .ALVIN L. JOHNSON, OF WORCESTER, IVISSACHUSETTS, ASSIGNOR TO W. GOULDING WARREN, F HOLDEN, MASSACHUSETTS LIFTING .TACK

Application led November 25, 1927.

rlhis invention relates to a lifting jack of the type in which a single lifting element is employed.

The principal object of the invention is to ,fprovide a construction in which the single lifting element, as for example, a screw or rack, can be raised to such aI height that it projects above the top of the base or casing a distance greater than the height of said base g, and at the saine time avoids the danger of dislodgement of the load by the turning of the screw. The invention also involves the construction of the lifting element in two or more parts, preferably three,

11% the upper part being substantially solid and the lower parts being arranged to be'located under it to support it, at certain times. I provide means whereby, when the lifting elenient descends into the casing far enough, the

{fj-'lower parts of the lifting element will automatically move laterally to allow the upper part to move down along the side of them and preferably between them and also, of course, to provide means whereby, when the 4-upper element is lifted up to a certain point,

the lower parts will automatically come together without attention. Here they not only support the upper part but constitute a continuation thereof adapted to be operated upon Coby the operating means in a continuous manner without any interruption. In this way the upper part of the lifting element can be made almost as long as the height of the casing and this entire part of the jack can be lifted above the top of the jack casing by a distance equal to the height of the lower part of the element minus so much of the same as may be needed to hold it in the casing and in operating contact with the operating ci; the change is about to take place on the Serial No. 235,583.

ascending motion or the position just after the change has taken place on the descending motion;

Fig. 8 is a view showing the upper part of the lifting element in section and its attached member at the bottom in elevation g' Fig. 1 is a View similar to Fig. 3 with the central section taken along a vertical plane at right angles thereto;

Fig. 5 is a sectional of Fig. 2;

Fig. 6 is a sectional view on the same line showing the parts in an entirely retracted position;

Fig. 7 is a sectional view of Dart of the device on the same plane as Fig. 2, showing the lower parts of the lifting element contracted together.

Fig. S is a sectional view taken on a vertical plane of a rack jack showing the same principle applied thereto;

view on the line 5 5 Fig. 9 is a sectional View of the same taken y on the line 9-9 of Fig. 8 and showing the upper rack section partly lowered into the casing;

Fig. 10 is an edge view of the rack show@ ing the lower part and the rod'below in section;

Fig. 11is a front view showing the racks in raised position;

Fig. 12 is a sectional view of part of the device on the same plane as Fig. 9 showing the lifting of the lower parts of the rack;

Fig. 13 is a sectional view on the line 13-13 of Fig. 9, and

Fig. 14 is a similar sectional view with the parts in the position they assume when the upper part of the rack is raised a little` the top 9 o-f the casing 10. This casing is provided interiorly with two pairs of conical or slanting surfaces l5 and 16 for a purpose to be described.

The lifting element consists of an upper part shown here in the form'of Vascrew 20 and having.a;rest/2l. for tle :work andtwo; lower parte 22, each one being shown in the form of an arcuate 1nember,lin this case, semicircu'lar in cross section. Tli-ese two parts have a screw thread constituting a"con tinuation of the thread on the part 20. lVhen these two parts 22 are brought together in the position shown in Figs..A l and Tthey. are continuous with the upper part of the lifting meinberi 2O.and, in'the form shown',V consti-z y tuteai continuousV screw. In. otherV- words, there is an area extending from top to bot. toingoflthiscontinuousfscrew which is provided .with .screw threadscooperating.- with the nut ll toliftthe-member '20,.not only when that member isili engagement with the scretwfthreads .ofthe nut, .butalso when the. two members 22 are in engagement'with it.

The upper vvp arti20; which .Ie call the solid part because it is in one piece, is provided with a .passage up through .itand'afrod .23"is adaptedfto bfey located .in :this passage. The part 2O is provided with a pair of guide pins- 24feprojecting. radially into .the interiorv and adaptedtoiengagef in longitudinallslots 25. which are; cut into ,theA rod 23; These. slots? extend nearly to the top of theurodrand," as shown' in iEigs.: .3 land 4, .the .rod .hangs fiom theepinst2-liwhen thel screw 20fis=-raised enough to lift the bottoiniofthe zrodzoffithe bottom -.of:the.casinfg;. T hisis. a telescoping construction allowingv the screw 2O to descend to .the .bottom iof' the: casing when thei screw jack is contracted. The rod 231lias a; ba'se26 adapted torest iony the .base/'ofthe casingxwhich .keeps-.the screw'. members from. rotating at all times. In the slot or slotsf25.) are au. pair. ofi oppositel springsa2.. These springs are fastened at the top'iinthe slots a by -ineansof pins.28. orother means and free to-islidein theslotsfat the bottonr. These. two :springs are adapted 'to' engagettheeintes. rior'coI-icave;surfacesI :of the .two lower parts 22 and force them out.v intothe position.

shown in Figs 2 when ythese lower parts .descend Lfrom the passage 29:down through the toprSof theffcasing.

The members 22 are provided with projec.- v

tioiiss 28; having slanting. upper4 surfaces adapted to'engage the conica-l orslantingsur.- faces l. 16 when. the two parts-22.:a;re=. forcedf aparte. This constitutes means for? forcing. them fto'getherv atthe bottom'A whenever they."

- areiraised. Itwilhbe noted tha-tithe bottoms oftheseanembers 22;'rest`on the plate 2.6' and?. when.. that i is raised: by' the raising'. of: the; screwx20, these two :parts are forcedito imove. upwardly'and they are alsoforced to nieve.: inwardly. atthe bottom on account of these.

conical surfaces. They are also forced to move inwardly at the top on account of engagement with the slanting surfaces 15.

In the operation of the device, assuming the lifting member to be contracted with the screw- 20clear down to the bottoin,.it will still engage .in the nut 1l.. The .shaftl beingnturned, the nut rotates and raises the screw 2O in the usual way with single screw jacks, without turning.y YVhen the screw lias reached thevpoint shown in Figs. 2, 3 and lthe ,continuation of the turning of the nut il'causes the screw 20 to move up still further; The plate .26 atthis time is positively moved upward with it and raises the two side parts 22. These'r are-1r forced together against the opposition-of the springs-27 by the conical surfaces l5 and 16 until the-two parts 22:v come in-to contact-with each other at the centeirwlien they constitute a second screw'. in continuation ofthesciew 20. This screw follows tlie'screw 2O into the-nut- 11- aiid yis raised in :the same mannei1` as the screw 2O without anyinterruption or change -inro tation ofzthe nut.

On lthe downward motion. the parts. 22.ai'e moved outwardlyby the springs 27 as soon as they. getE out of the'passage 29. This outward motion Lis controlled by the-conical sui'- faces 15 and also controlled at the bottom by\'the\'c'onical surfaces-16. The parts a-ie so'v proportioned thatthey will move outwardly.

far enough to permitfthe screw 20 to descend between-them, which is shown in Fig.6. As this screw descends itv forces inwardly the twofsprings 2Tbutthat has no effect on tl operation as there is nothingnow to'move the. two parts22. The screw 2() therefore can bewlowered until .its bottom rests against-the plate'z26.

In either way itwill be: seen that a jack is furnishedfinwhich the entiie length of theupper part 2O can be-:lifted materially above'. the :top ofthe ackv and theV entire lieightof' isnearly three times the jack, when expanded, what itfis whenfco-ntracted. Yet the screws do not turn atany-tinie and there isno danger'of working `the load off the rsup13 oitf2lby any yturningfor other motionof the screws T-heconstruction is simple andthe operation entirely automatic.A The changes in position take pla-ce without jar orbindingfa-nd the. lifting ofthe-load 'does not become harder due. to any. binding ofv the'screws, as with one screw inside another, when it is lifted to nearly. the- 'maximum .height but. ity is practically always the same.. The parts are simpler-and can be' in ade by economie shop methods.

In the form shown on the'second sheet the principles. aresubstantially the same as appliedto a rack jack; Here the casing() is provided .with pafwls 3l operated by a--lever 33 and controlled bya'zcani lever 32 asis usual in -i'ack-jaclrs. The casingiis provided lwith a guide 39 at: theftop for guiding the racks.

The casing 30 is provided with two pairs of slanting surfaces 35 and 36 having the same purposes as the conical surfaces 15 and 16 in the other form.

The upper part of the lifting element is shown in the form of a rack 40 having teeth along one side and provided with a support 41 for the load. The lower part of the lifting element consists of two racks 42 having a similar set of teeth. A rod 43 is connected with the part 40 of the rack by pins 44 and is provided with grooves 45 along its sides and with a lifting plate 46 fixed to its lower end. In these grooves is a double spring 47 which is shown here as in one piece and operating in all respects like the springs 27. The two rack members 42 are provided with projections 48 slanting on top and extending in opposite directions.

The operation of this jack will be understood from the description of the operation of the screw ack given above. It is operated by the lever 33 in the sam-e manner as any rack jack. The descent of the rack from the position shown in Fig. 8 to the position shown in Fig. 9 allows the springs 47 to force the racks 42 apart far enough to allow the rack 40 to descend between them. The racks 42 cannot separate. fully until the projections 48 come down low enough to enter under the slanting surfaces 36 and they rest on the plate 46. As the rack 40 descends it compresses the springs 47 as in the other case.

Upon rising, the opposite action takes place 'and the positive force of lifting of the racks 42 by the plate 46, as the rack 40 rises, causes the slanting surfaces 35 and 36 to contract the racks 42 in opposition to the springs 47. Thus they come together under the rack 40 and in due season are operated upon by the pawls 3l to force the double length rack up as shown in Fig. 8.

The rack is continuous from top to bottom and the rod 43, on account of its connection with the rack 40 and its support of the racks 42, prevents the swinging of the rack 40 and insures a rigid construction for supporting the load.

Although I have illustrated and described only two forms of the invention I am aware of the fact that other modifications can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims. Therefor-e, I do not wish to be limited to the details herein disclosed, but what I do claim is l. In a. lifting jack, the combination with a casing and an operating mechanism carried thereby, of a lifting member comprising a plurality of parts all adapted to be received in the casing with their lower ends at substantially the same level side by side and in upright position when retracted, and arranged and adapted to be moved directly upwardly through the top of the casing byY said operating mechanism one on top of another in vertical alignment.

2. In a lifting jack, the combination with a casing and an operating mechanism carried thereby, of a lifting member comprising a plurality of-parts all adapted to be arranged vertically side by side within the casing, one

of them being then in operative engagement with the operating mechanism, and means whereby, when said part is moved upwardly to project above the casing, the lower part will move automatically to a position under it and come into operative engagement with said operating mechanism.

3. .In a lifting jack, the combination with a casing and an operating mechanism carried thereby, of a lifting member comprising a plurality of parts all adapted to be arranged side by side within the casing, one of them being then in operative engagement with the operating mechanism, and means whereby, when said part is moved upwardly the lower part will move automatically to a position under it and come into operative engagement with said operating mechanism.

4. In a lifting jack, the combination with a base and an operating means, of a lifting member comprising two parts having a continuous area to cooperate with the operating means for raising or lowering saidk lifting member, and one of said parts comprising two parts normally located side by side in the base, and means for moving the said two parts laterally when the upper part has risen to its top, to bring said areas into registration with each other and permit the operating means to act on the lower part of the lifting member.

5. A lifting jack comprising a lifting member consisting of three parts, two of said parts being laterally separable to provide a space between them for receiving the other part when it is lowered, theV ends of the separable parts when they are in contact being located under said other part when it is raised above the separable parts.

6. A lifting jack comprising a lifting member consisting of three parts, two of said.

parts being laterally separable to provide a space between them for receiving the other part which is adapted to be supported on the ends of the two separable parts when they are in contact with each other, the two parts combined having the same cross section as the other part, and being provided with means by which they can be raised, the other parts also having similar means continuous therewith.

7. In a. lifting jack, the combination with a hollow base, of a solid lifting member, and a lifting member consisting of a plurality of parts, means whereby, when the first lifting member is raised in the base, the parts of the second lifting member will be caused to come together under-v the iiist named mmrberiv to:V supportv and f lift; it,:. and `*means :where-by; when the two lifting membersffarezlowered. to a: position in which thesecond Iiftingmem- T ber is locatedentirelyin'thetrbaseatheaparts; thereof will remainzainivertical positionand will=separate to allow'thel first-:lifting mem-- ber'to be lowered Abetween them;

8'.' AIn faalifting ack; .the combinationA with i 10'? a: casing and arotatablenutzcarried thereby;I

of ia screw;having an :upp'eripartiin l:onefp'ieceand. a lower part, continuons therewitlnlbutr; in a `plurality f of:movable-ipieces,f .and fmeans'f whereby, vuponl loweringfthe screw'funtil1itsf: T lower end projects-below the mit/intovthel casinggthe lowerrpieceswill =move sideways automaticallyI to' allow :the-A upper screw 'pa-rtf, to :descend `into the casingrat theirsideap 9; In a lifting aclq vthe:combinationwithi 2mavvcasing. and a-rotatable nut v'carriedthereby, of a :screw having anupperipartin lone-pieceand r a: zlower part, ,continuous therewith, .blit'f in .a-plurality ofimovable pieces, and. means; whereby,', upon raising 1 the. screw;y the-'alowerf pieces will movesideways automaticallyltoi a position.: underftheiupper:` screw part' to support"v theupper: part; andi engage. the nut to Aforce*thefgupperi partabove theetopf :.of 1.' the .casinoni Y l0. Ina lifting jack; the combinationwith, a' casing land anoperatingginuh: ofa; scre vr threaded. lifting `member;'comprising anup-f: per part havingla screwthread 'adapted 5to: cooperate with the -nutitoliftitheimember Ywith-z out 'turning 'it, said V liftinfg;imemloerials'o `come prisingY a plurality of; separatei'flowerrparts:Y which,v when brought together; .form zasscrew" continuous witlrthe screwfof the upper 'pa-rtgaA also adapted to cooperate with saidilnutrforz' mthe same purpose', andra rod .slida'bleiin the upper part' and 1 connected withr itz'to': movef: upwardly withwit and Ahavingrneans wherebyl said Alower screw "parts `will :rise with :the rod:` 1l. In a liftinggj ack, thecombinationi'withe 455 acasinghaving-an:openingfatithef top; and;

an'. operatingg nut5 of: a screwV threaded 1lift'. ing member rcomprising-an. upvperrpart have ing; a continuous-,screw lthread xadapted to cooperatewith.the` nut to lift the memberfwithe. out-turning it, said lifting member: also com. A prisingf a: plurali tyrof lseparate partswwhichgr, when broughttogether; form a :screw contin'f nous-with pthefscrew 'of' the uppert part, also adapted tto coopera-te with said nut-i fori` thee 555 samefpurpose, a rod slidable in them-p; ripartf and .connected wi th' .it .to move upwarc ly with". it when -thez upper lpart .is moved (out I of :the i casing; and ihaving anpla'tefon :the bottom on a which rest the bottoms of said lower screwm part-s, wherebyl said lower screw.- parts will rise with; theV rod; and yielding@ meansl ,'carried by said rodv and engaging the inne-resides e ofthe lower-screw parts-forforcinglthem out.- away from eachz other; whenever: they5 are: "5 Yfree to move,A the. casi-ng-havinggmeans coop-i nsaegeym ei-atingwith/.thezlow'ers'erew parts for allow-` ing; them to; move .outwardly under the k,im fluence offthe yielding means when housed lat the bottom of the casing andfor forcing them together aboutthe rod under the vupper part whenlift'ed to =the.top ofthe casing.:-

12.'.In arzliftingj ack, .the combination withl a casingshavingnan opening att-he top,r andi an operatngnut, of. a. screw threaded lifting member comprising an upperpart having a screw-thread adapted to cooperate 4with thev nut'. to :Jliftthexmember without' turning, it, Y said lifting member also comprising.; a plu-1 ralityfof'separate-.parts which5 when brought together; form ascrew'continuous with'zthe.- screwfofthe upperzpart, alsoadapted to* cooperate withsaid nutforf the rsame purpose, arod slidabletin the upper parta-nd connected with it to move upwardlywith it and having. meanswhereby said lower screwfparts will rise with' the rod,- and apair offsprings carried by the rod and normally pressing aga-inst the-.'lowerfscrew parts, ,thecasing having az pair ofI slanting, surfacesV at the bottom' andv afpair of slanting surfaces at the top forengaging said lower parts and forcing. them inwardly against the spring7 about the rod, and under the upper screw .partvwhen the low' ergscrewi partsfare llifted .to a position to start to proj ectr through sa-idopening:

13. In a liftingjack7 .the combinationwith a-casing having..anxopeningzat the top, and: an operating nut, of a: screw threaded lift-A ing member comprising an'upper part having ariscrewA thread and a plurality of'separate partswhich; when brought together, form a.

screw continuous with thel screwaof the upperl part7 a rod inthe upper*part=andconnected` with it, Aand yielding-meansv carried by saidl rod and engagingthe inner sidesoffth'e lower screw .parts forrforcing, them outv away from each other whenever they areifree'to move', the casing havingmeans cooperating with the lowerscrewf parts for forcing them together about the-rod under-the 'uppe-rvpart when zlift'edito the topof the casinfr,

143 Ar'liftinggrackfor: a jack comprisingl an upper member and two lower members" independently movable sideways, and :a rod slidable'in the upperfmember. and dependingfrom'. the; bottom thereof i'having mea-nsf for:-

supportingthe side members at sucha levely that their'tops lare just under Athe bottom ofA the upperxmember, .whereby the three fmem-Y bers together constituteA a continuous-rack.

15'.- A liftingfmember fora'rjack comprising a screw in three parts, one p art beingcy lindrical iand the=.;other1two'partsfarcuiate in transverse cross'section, saidftwo :parts beingi separable radially toihazve aspacewbetween them sufficientito receive the 'first mentioned para. y

16. In a lifting ackg the combination with ai casingand anoperatingfmeans carried thereby, of av lifting-member: comprising am srs-1 upper part, a rod telescoping therein, and a lower part supported by the rod and movable sideways to permit the upper part to descend into the casing past the lower part, said rod hanging from said upper part when raised to stabilize the lifting member in the casing.

17. A jack comprising, in combination, a standard, a screw, with upper section and lower .split section, all operable into and out of said standard, and means for spreading in half the said split lower section of the screw to permit said upper section to pass within it.

18. A jack comprising, in combination, a standard, a sectional screw keyed to said standard and slida-ble therein, and means within said screw for spreading one of said sections to permit another section to slide within it.

19. A jack comprising, in combination, a standard, a sectional screw with lower portion adapted to be spread open to permit the upper portion to pass within it, means within the screw for spreading said lower portion when within the standard, and means within the standard adapted to close said split portion of screw as the screw travels out of said standard.

20. A. jack comprising, in combination, a standard, a sectional screw keyed to said standard and slidable therein, a spring arranged to spread one section of the screw within the standard to permit passage within it of another section of the screw, and means within said standard and operable during outward travel of the screw for closing said spread screw section.

2l. A jack comprising, in combination, a standard, a sectional screw with lower portion adapted to be spread open to permit the upper portion to pass within it, spring arms tending to spread said lower portion and inclined surfaces at upper and lower ends of said standard adapted to permit said spreading when said lower portion is wholly within said standard` and adapted to close said lower section as it moves upward out of said standard.

In testimony whereof I have hereunto aflixed my signature.

ALVIN L. JOHNSON. 

